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Full-Text Articles in Chemistry

Refining A Flow Injection Analysis Method For Trace Concentrations Of Iron In Seawater, Brooke I. Stafford, Liam W. Hodgson, Noah S. Schuhmann, Elijah J. Vestal, Claire P. Till Jun 2026

Refining A Flow Injection Analysis Method For Trace Concentrations Of Iron In Seawater, Brooke I. Stafford, Liam W. Hodgson, Noah S. Schuhmann, Elijah J. Vestal, Claire P. Till

IdeaFest: Interdisciplinary Journal of Creative Works and Research from Cal Poly Humboldt

Iron is an essential micronutrient required for the growth of phytoplankton, the base of the oceanic food chain. Iron exists in the ocean in extremely low concentrations, limiting primary productivity in ~⅓ of the surface ocean, and can be affected by physical processes such as upwelling of water masses, and by biological and chemical processes within the water. In order to further our understanding of iron availability in the ocean, here we refine and improve our understanding of an analytical method to measure nanomolar iron in seawater. The method used is an adaptation of Lohan et al. (2006), a flow …


Thermally Induced Color Changes In Iron Oxide Pigments Used In Architectural Coatings, Han Diep Jun 2026

Thermally Induced Color Changes In Iron Oxide Pigments Used In Architectural Coatings, Han Diep

Master's Theses

The 2025 Palisades Fire was one of the most destructive wildfires in the history of Los Angeles, destroying thousands of structures and severely impacting the communities after. This widespread destruction demonstrated an urgent need for more effective wildfire prevention strategies. Architectural coatings do not only provide aesthetics and protection against environmental conditions but can also function as a thermal indicator when a fire breaks out. This study examines the thermally induced color transformation of iron oxide pigments, commonly used in earthtone paint, to provide information relevant to CAL FIRE for improved analysis of wildland-urban interface (WUI) fire behavior and mitigation …


Catalytic Synthesis Of Iron-Doped Graphitic Aerogels From Poly(Phloroglucinol-Terephthalaldehyde – Urethane) Precursors, Stephen Yaw Owusu, Rushi U. Soni, Chariklia Sotiriou-Leventis Dec 2025

Catalytic Synthesis Of Iron-Doped Graphitic Aerogels From Poly(Phloroglucinol-Terephthalaldehyde – Urethane) Precursors, Stephen Yaw Owusu, Rushi U. Soni, Chariklia Sotiriou-Leventis

Chemistry Faculty Research & Creative Works

We report a new class of graphitic carbon aerogel precursors based on iron oxide-doped poly(phloroglucinol-terephthalaldehyde–urethane) (T-POL/PU-FeOx) networks. The hybrid polymeric network incorporates a rigid aromatic triisocyanate, tris(4-isocyanatophenyl)methane, which reacts in situ with the hydroxyl groups of phloroglucinol to form a polyurethane-containing framework. Monolithic aerogels derived from this system undergo catalytic graphitization at significantly reduced temperatures (800–1500 °C) compared to conventional graphitization (2500–3300 °C). An oxidative ring fusion aromatization step (240 °C, air) prior to pyrolysis enhanced the degree of graphitization. The resulting graphitic aerogels were characterized by XRD, Raman spectroscopy, TGA, TEM, SEM, XPS, and N₂ sorption porosimetry. Compared to …


Preparation And Characterization Of Rhfe/G-C3n4 Nanoparticles For Efficient Hydrolysis Of Sodium Borohydride, Merve Uçar Kaya, Mehmet Yurderi̇, Mehmet Zahmakiran Feb 2025

Preparation And Characterization Of Rhfe/G-C3n4 Nanoparticles For Efficient Hydrolysis Of Sodium Borohydride, Merve Uçar Kaya, Mehmet Yurderi̇, Mehmet Zahmakiran

Turkish Journal of Chemistry

Highly effective graphitic carbon nitride-supported RhFe Nanoparticles (denoted as RhFe/g-C3N4) were prepared using a simple wet impregnation-reduction method for the hydrolysis of sodium borohydride (NaBH4). The obtained RhFe/g-C3N4 catalyst was characterized using advanced analytical/spectroscopic techniques such as inductively coupled plasma-optical emission spectroscopy (ICP-OES), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Powder X-ray diffraction (P-XRD), X-ray spectroscopy (XPS), and fourier transform infrared spectroscopy (FT-IR). The catalytic activities of RhFe/g-C3N4 catalysts with varying Rh/Fe molar ratios were investigated, demonstrating superior catalytic activity compared to monometallic Rh and Fe. The initial turnover frequency (TOF) value of the Rh0.48Fe0.52/g-C3N4 catalyst was calculated as …


Mechanism Of Iron-Catalyzed Oxidative Α-Amination Of Ketones With Sulfonamides, Gloria M. Parrales, Nina C. Hollin, Fubin Song, Yangyang Lyu, Anne-Marie O. Martin, Alexandra E. Strom Aug 2024

Mechanism Of Iron-Catalyzed Oxidative Α-Amination Of Ketones With Sulfonamides, Gloria M. Parrales, Nina C. Hollin, Fubin Song, Yangyang Lyu, Anne-Marie O. Martin, Alexandra E. Strom

Chemistry: Faculty Publications

We report the mechanism of the iron-catalyzed oxidative α-amination of ketones with sulfonamides. Using linear free energy relationships, competition experiments, and identification of reaction intermediates, we have found that the mechanism of this reaction proceeds through rate-limiting electron transfer to 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) from an iron enolate in the process of forming an α-DDQ adduct. The adduct then serves as the electrophile for substitution with sulfonamide nucleophiles, accelerated by iron and additional DDQ. This mechanistic study rules out formation of an α-carbocation intermediate and purely radical mechanistic hypotheses.


Towards Carbon Dioxide Reduction: Synthesis And Characterization Of Ccc-Nhc Pincer Iron Complexes., Joshua Mensah May 2024

Towards Carbon Dioxide Reduction: Synthesis And Characterization Of Ccc-Nhc Pincer Iron Complexes., Joshua Mensah

Theses and Dissertations

The industrial revolution came with its downside of emission of greenhouse gases into the atmosphere. The NOAA reported in 2019 that, of the greenhouse gases emitted into the atmosphere, CO2 contributed to about 80% of the increased greenhouse gases hence the need for CO2 Sequestering and Storage (CSS) and ultimately leading to Carbon Capture and Recycling (CCR) as a viable option to convert CO2 into useful forms. The race to find the best catalyst for CCR has led to the synthesis of many organometallic compounds. Pincer complexes catalyzed CO2 reduction has gained notoriety recently because of the tunability and robustness …


Hydroxyl- Terminated Dendrimers With Sulfonimide Linkers As Binders For Metals Of Industrial Significance, Khaleel Abu Sbeih, Mohammad Al Harahsheh Feb 2024

Hydroxyl- Terminated Dendrimers With Sulfonimide Linkers As Binders For Metals Of Industrial Significance, Khaleel Abu Sbeih, Mohammad Al Harahsheh

Turkish Journal of Chemistry

First- and second-generation hydroxyl- terminated dendrimers were prepared starting from a 1,3-diaminopropane core and sulfonimide linkers. A first-generation mesitylene-derived dendrimer was also prepared with the same terminals. The dendrimers were then reacted with Fe3+, Al3+, and UO22+ separately in order to apply the dendrimers for binding these metals, which have important industrial applications and pose environmental problems simultaneously. The prepared dendrimers were also shown to bind Fe3+ selectively from mixtures with Al3+.


Synthesis, Characterization, And Reactivity Studies Of Pyridine Dipyrrolide Iron-Carbene Complexes With Electronically Distinct Carbene Moieties, Jose G. Rodriguez Jan 2024

Synthesis, Characterization, And Reactivity Studies Of Pyridine Dipyrrolide Iron-Carbene Complexes With Electronically Distinct Carbene Moieties, Jose G. Rodriguez

Graduate Theses, Dissertations, and Problem Reports (ETD)

First, three (MesPDPPh) iron carbene complexes with electronically distinct carbene moieties were synthesized. These transitional iron carbene complexes were first characterized by 1H nuclear magnetic resonance (NMR) spectroscopy as their spectra showed paramagnetically shifted resonances. Additionally, their respected solid state structures were collected via X-ray diffraction. The two donor/acceptor iron carbene complexes [(MesPDPPh)Fe(C(CO2Me)(4-FPh) and (MesPDPPh)Fe(C(CO2Me)(4-MeOPh)] demonstrated a weak Fe-O interaction between the iron center and ester function group while the (MesPDPPh)Fe(IMe) displayed a C2v symmetric structure in the …


Investigation Of Zinc And Iron In Wildflower Honey, Savannah Simpson Dec 2023

Investigation Of Zinc And Iron In Wildflower Honey, Savannah Simpson

Honors Theses

Honey acts as a valuable food source for both animals and humans. When found in contaminated environments, there is an increased likelihood that honey samples will have high metal concentrations. It has been discovered that honey concentrations in metals can be different based on location. This experiment aims to determine the amount of two valuable metals, zinc, and iron, in various honey sources. These metals can be important to the human body because they help boost immunity and allow the body to carry out the functions required for survival. However, if these elements are present in copious quantities, then it …


Substituent Effects And Mechanistic Insights On The Catalytic Activities Of (Tetraarylcyclopentadienone)Iron Carbonyl Compounds In Transfer Hydrogenations And Dehydrogenations, Bryn K. Werley, Xintong Hou, Evan P. Bertonazzi, Anthony Chianese, Timothy W. Funk Oct 2023

Substituent Effects And Mechanistic Insights On The Catalytic Activities Of (Tetraarylcyclopentadienone)Iron Carbonyl Compounds In Transfer Hydrogenations And Dehydrogenations, Bryn K. Werley, Xintong Hou, Evan P. Bertonazzi, Anthony Chianese, Timothy W. Funk

Chemistry Faculty Publications

(Cyclopentadienone)iron carbonyl compounds are catalytically active in carbonyl/imine reductions, alcohol oxidations, and borrowing hydrogen reactions, but the effect of cyclopentadienone electronics on their activity is not well established. A series of (tetraarylcyclopentadienone)iron tricarbonyl compounds with varied electron densities on the cyclopentadienone were prepared, and their activities in transfer hydrogenations and dehydrogenations were explored. Additionally, mechanistic studies, including kinetic isotope effect experiments and modifications to substrate electronics, were undertaken to gain insights into catalyst resting states and turnover-limiting steps of these reactions. As the cyclopentadienone electron density increased, both the transfer hydrogenation and dehydrogenation rates increased. A catalytically relevant, trimethylamine-ligated iron …


Electrochemical Approaches To Life-Support Resources In Space Missions And Nuclear Technologies: Hydrogen Peroxide And Uranium Films, Armando Manuel Pena-Duarte Aug 2023

Electrochemical Approaches To Life-Support Resources In Space Missions And Nuclear Technologies: Hydrogen Peroxide And Uranium Films, Armando Manuel Pena-Duarte

Open Access Theses & Dissertations

Space race has developed several technological advances that have achieved and continue to achieve the success of space missions in the aerospace timeline. Currently, the number of space technical and scientific innovations is still growing––demanding new materials and developments for extreme performing applications of fuel cells, batteries, supercapacitors, and systems of nuclear energy. Space missions require life-support solutions, auto-sustainable closed-loop living environments, cleaning and sanitizing solutions against pathogens, and safe nuclear-based resources of energy––with fissile materials with well-controlled dimensions within the core fuel elements. Likewise, to guarantee safety conditions, reduce costs, and facilitate operational logistics, space missions must reduce their …


Authigenic Iron Is A Significant Component Of Oceanic Labile Particulate Iron Inventories, Laura E. Sofen, Olga A. Antipova, Kristen N. Buck, Salvatore Caprara, Lauren Chacho, Rodney J. Johnson, Gabriella Kim, Peter Morton, Daniel C. Ohnemus, Sara Rauschenberg, Peter N. Sedwick, Alessandro Tagliabue, Benjamin S. Twining Jan 2023

Authigenic Iron Is A Significant Component Of Oceanic Labile Particulate Iron Inventories, Laura E. Sofen, Olga A. Antipova, Kristen N. Buck, Salvatore Caprara, Lauren Chacho, Rodney J. Johnson, Gabriella Kim, Peter Morton, Daniel C. Ohnemus, Sara Rauschenberg, Peter N. Sedwick, Alessandro Tagliabue, Benjamin S. Twining

OES Faculty Publications

Particulate phases transport trace metals (TM) and thereby exert a major control on TM distribution in the ocean. Particulate TMs can be classified by their origin as lithogenic (crustal material), biogenic (cellular), or authigenic (formed in situ), but distinguishing these fractions analytically in field samples is a challenge often addressed using operational definitions and assumptions. These different phases require accurate characterization because they have distinct roles in the biogeochemical iron cycle. Particles collected from the upper 2,000 m of the northwest subtropical Atlantic Ocean over four seasonal cruises throughout 2019 were digested with a chemical leach to operationally distinguish labile …


Potential Interactions Between Diatoms And Bacteria Are Shaped By Trace Element Gradients In The Southern Ocean, Alexa R. Sterling, Laura Z. Holland, Randelle M. Bundy, Shannon M. Burns, Kristen N. Buck, P. Dreux Chappell, Bethany D. Jenkins Jan 2023

Potential Interactions Between Diatoms And Bacteria Are Shaped By Trace Element Gradients In The Southern Ocean, Alexa R. Sterling, Laura Z. Holland, Randelle M. Bundy, Shannon M. Burns, Kristen N. Buck, P. Dreux Chappell, Bethany D. Jenkins

OES Faculty Publications

The growth of diatoms in the Southern Ocean, especially the region surrounding the West Antarctic Peninsula, is frequently constrained by low dissolved iron and other trace metal concentrations. This challenge may be overcome by mutualisms between diatoms and co-occurring associated bacteria, in which diatoms produce organic carbon as a substrate for bacterial growth, and bacteria produce siderophores, metal-binding ligands that can supply diatoms with metals upon uptake as well as other useful secondary compounds for diatom growth like vitamins. To examine the relationships between diatoms and bacteria in the plankton (diatom) size class (> 3 mu m), we sampled both …


Atmospheric Input And Seasonal Inventory Of Dissolved Iron In The Sargasso Sea: Implications For Iron Dynamics In Surface Waters Of The Subtropical Ocean, Peter N. Sedwick, Bettina M. Sohst, K. N. Buck, S. Caprara, R. J. Johnson, D. C. Ohnemus, L. E. Sofen, A. Tagliabue, B. S. Twining, Tara E. Williams Jan 2023

Atmospheric Input And Seasonal Inventory Of Dissolved Iron In The Sargasso Sea: Implications For Iron Dynamics In Surface Waters Of The Subtropical Ocean, Peter N. Sedwick, Bettina M. Sohst, K. N. Buck, S. Caprara, R. J. Johnson, D. C. Ohnemus, L. E. Sofen, A. Tagliabue, B. S. Twining, Tara E. Williams

OES Faculty Publications

Constraining the role of dust deposition in regulating the concentration of the essential micronutrient iron in surface ocean waters requires knowledge of the flux of seawater-soluble iron in aerosols and the replacement time of dissolved iron (DFe) in the euphotic zone. Here we estimate these quantities using seasonally resolved DFe data from the Bermuda Atlantic Time-series Study region and weekly-scale measurements of iron in aerosols and rain from Bermuda during 2019. In response to seasonal changes in vertical mixing, primary production and dust deposition, surface DFe concentrations vary from ∼0.2 nM in early spring to >1 nM in late summer, …


Exploration Of Metal-Carbonyl Complexes For Decarbonylation Reactions, Rebekah C. Krupa Jan 2023

Exploration Of Metal-Carbonyl Complexes For Decarbonylation Reactions, Rebekah C. Krupa

Graduate Theses, Dissertations, and Problem Reports (ETD)

In recent years, transition metal-mediated decarbonylation reactions have emerged as an alternative to conventional cross-coupling methods due to the advantages associated with the use of carbonyl-containing functionalities as coupling electrophiles instead of organohalides found in traditional cross-coupling reactions. This, coupled with the ubiquity of carbonyl-containing compounds in pharmaceuticals and non-biodegradable chemicals, has led to the interest in developing efficient systems for transition metal-catalyzed decarbonylation. However, these reactions are commonly limited to stoichiometric amounts of metal reagents due to the strong metal-carbonyl bond formed during transition metal-mediated decarbonylation. With the goal of gaining a better mechanistic understanding of CO dissociation in …


Deciphering The Molecular Circuitry That Controls Iron Regulation In Non-Pathogenic Yeast, Debolina Hati Oct 2022

Deciphering The Molecular Circuitry That Controls Iron Regulation In Non-Pathogenic Yeast, Debolina Hati

Theses and Dissertations

The trace metal iron is essential for the survival of almost all living organisms. It is a co-factor for many proteins involved in a variety of vital functions such as respiration, nitrogen fixation, and DNA biosynthesis, to name a few. Iron homeostasis in non-pathogenic fungi such as Schizosaccharomyces pombe has been extensively studied over the past few decades to better understand how intracellular iron is regulated under different environmental conditions. Iron regulation in S. pombe is controlled by two Fe-responsive transcriptional repressors known as Php4 and Fep1. Both rely on iron-sulfur (Fe-S) clusters as signals to balance iron acquisition, storage, …


Characterization Of The Interaction Between Grx4-Bol2 And The Iron-Responsive Transcription Factor Aft1 In Candida Glabrata, Evan A. Talib Oct 2022

Characterization Of The Interaction Between Grx4-Bol2 And The Iron-Responsive Transcription Factor Aft1 In Candida Glabrata, Evan A. Talib

Theses and Dissertations

Iron is an indispensable protein cofactor that plays a critical role in biological functions such as cellular respiration. However, excess iron causes cellular damage via the generation of reactive oxygen species. To obtain optimal intracellular iron levels, eukaryotic cells have developed mechanisms to tightly regulate iron levels. The molecular mechanism for iron regulation in the pathogenic yeast Candida glabrata has not yet been explored, although this yeast bears iron regulation pathways that are very similar to the model yeast Saccharomyces cerevisiae. Understanding how C. glabrata regulates iron levels is critical for the treatment of infections caused by this opportunistic …


Mechanistic Insights Into An Iron-Responsive Repressor, Fep1, From Schizosaccharomyces Pombe, Allison Nicole Kimsey Oct 2022

Mechanistic Insights Into An Iron-Responsive Repressor, Fep1, From Schizosaccharomyces Pombe, Allison Nicole Kimsey

Theses and Dissertations

Iron is an essential metal cofactor required for a variety of biochemical pathways in most living organisms. In recent years, the nonpathogenic fungi Schizosaccharomyces pombe has been used to study iron regulation and uncover the molecular mechanisms for controlling intracellular iron levels. Some of these regulation pathways are conserved with those of pathogenic fungi, making these studies applicable for the future development of antifungals that target iron homeostasis. In S. pombe, the GATA-type transcriptional repressor Fep1 is responsible for repressing iron uptake genes during times of iron abundance. Previous reports have proposed that the binding of an iron-sulfur (Fe-S) …


Synthesis And Characterization Of Biomimetic Co And Fe Complexes With Trispyrazolylborate Ligands, Praveen Kumar Jul 2022

Synthesis And Characterization Of Biomimetic Co And Fe Complexes With Trispyrazolylborate Ligands, Praveen Kumar

Dissertations (1934 -)

Numerous reactions of biological and environmental significance are catalyzed by dioxygenases that incorporate both atoms of O2 into the substrate. These enzymes require a transition-metal cofactor for activity, typically a mononuclear nonheme iron center, although dioxygenases with first-row transition metal ions (Mn, Co, Ni) have been discovered. This dissertation focuses on synthetic studies based on mononuclear dioxygenases found in bacterial pathways for the breakdown and assimilation of inert organic compounds, including human-generated pollutants. Such enzymes are essential for bioremediation technologies used to restore contaminated soils and groundwaters. While crystallographic studies have revealed the active-site structures of various types of dioxygenases, …


Harmful Algal Blooms In Caesar Creek Lake And Their Relationship To Riparian Cover, Morgan C. Grunden Jan 2022

Harmful Algal Blooms In Caesar Creek Lake And Their Relationship To Riparian Cover, Morgan C. Grunden

Browse all Theses and Dissertations

Caesar Creek Lake (CCL) in Warren County, OH has recently been experiencing harmful algal blooms (HABs) which are most likely attributed to an excess of phosphorus (P) from fertilizers and manures applied to surrounding fields. Sediments act as a sink for P later supplying a source of P in lakes for HABs when waters become thermally stratified and anoxic. This study seeks to determine the relationship between HABs in CCL and riparian cover at the main tributaries, Anderson Fork and Caesar Creek. In order to do this, sediment samples were collected from four sample sites along Anderson Fork and three …


Computational Study On The Nucleation Of Polyoxovanadate-Alkoxide Clusters, S M Gulam Rabbani Jan 2022

Computational Study On The Nucleation Of Polyoxovanadate-Alkoxide Clusters, S M Gulam Rabbani

Dissertations and Theses

Polyoxovanadate-alkoxide (POV-alkoxide) clusters are a new class of electroactive species with potential electrochemical applications in redox catalysis, energy storage, and optoelectronics. These clusters' redox properties can be tuned by the functionalization via heterometallic installation and changing alkoxide ligands. However, the formation mechanism of these POV-alkoxides in the solvothermal process is unknown, limiting the rational design to improve their electronic properties. This dissertation reports the speciation study of POV-alkoxide clusters, which is fundamental to controlling and manipulating the evolution of transient species during their nucleation and tuning the final product's properties. Chapter 2 and chapter 3 describe our computational study of …


A Compendium Of Inorganic Photochemistry: Synthetic And Spectroscopic Discoveries, Sebastian B. Vittardi Sep 2021

A Compendium Of Inorganic Photochemistry: Synthetic And Spectroscopic Discoveries, Sebastian B. Vittardi

Chemistry and Chemical Biology ETDs

This dissertation reports and examines contributions made in the advancement of inorganic photochemistry. Empirically driven assessments are allotted to the interplay between ligand sets, excited states, and photochemistry observed in metal complexes. A methodical spectroscopic examination is provided for oligothiophene-sensitized lanthanides. Their excited state dynamics were elucidated by femtosecond pump-probe spectroscopy and used to develop a model explaining their wavelength-dependent dual functionality. Iron (II) cyanide and isocyanides are evaluated to identify the efficacy of strong-field ligands in promoting charge-transfer excited states. Fundamentals of ligand field theory helped conceptualize the synthetically tunable parameters and effects transposed to their absorption dynamics. Transition …


Taxonomic And Nutrient Controls On Phytoplankton Iron Quotas In The Ocean, Benjamin S. Twining, Olga Antipova, P. Dreux Chappell, Natalie R. Cohen, Jeremy E. Jacquot, Elizabeth L. Mann, Adrian Marchetti, Daniel C. Ohnemus, Sara Rauschenberg, Alessandro Tagliabue Jan 2021

Taxonomic And Nutrient Controls On Phytoplankton Iron Quotas In The Ocean, Benjamin S. Twining, Olga Antipova, P. Dreux Chappell, Natalie R. Cohen, Jeremy E. Jacquot, Elizabeth L. Mann, Adrian Marchetti, Daniel C. Ohnemus, Sara Rauschenberg, Alessandro Tagliabue

OES Faculty Publications

Phytoplankton iron contents (i.e., quotas) directly link biogeochemical cycles of iron and carbon and drive patterns of nutrient limitation, recycling, and export. Ocean biogeochemical models typically assume that iron quotas are either static or controlled by dissolved iron availability. We measured iron quotas in phytoplankton communities across nutrient gradients in the Pacific Ocean and found that quotas diverged significantly in taxon‐specific ways from laboratory‐derived predictions. Iron quotas varied 40‐fold across nutrient gradients, and nitrogen‐limitation allowed diatoms to accumulate fivefold more iron than co‐occurring flagellates even under low iron availability. Modeling indicates such “luxury” uptake is common in large regions of …


Dark Iron-Catalyzed Reactions In Acidic And Viscous Aerosol Systems Efficiently Form Secondary Brown Carbon, Hind A. Al-Abadleh, Md Sohel Rana, Wisam Mohammed, Marcelo I. Guzman Dec 2020

Dark Iron-Catalyzed Reactions In Acidic And Viscous Aerosol Systems Efficiently Form Secondary Brown Carbon, Hind A. Al-Abadleh, Md Sohel Rana, Wisam Mohammed, Marcelo I. Guzman

Chemistry Faculty Publications

Iron-driven secondary brown carbon formation reactions from water-soluble organics in cloud droplets and aerosols create insoluble and soluble products of emerging atmospheric importance. This work shows, for the first time, results on dark iron-catalyzed polymerization of catechol forming insoluble black polycatechol particles and colored water-soluble oligomers under conditions characteristic of viscous multicomponent aerosol systems with relatively high ionic strength (I = 1–12 m) and acidic pH (∼2). These systems contain ammonium sulfate (AS)/nitrate (AN) and C3–C5 dicarboxylic acids, namely, malonic, malic, succinic, and glutaric acids. Using dynamic light scattering (DLS) and ultra high pressure liquid chromatography-mass spectrometry (UHPLC-MS), …


Iron Speciation In Pm2.5 From Urban, Agriculture, And Mixed Environments In Colorado, Usa, Joseph R. Salazar, David J. Pfotenhauer, Frank Leresche, Fernando L. Rosario-Ortiz, Michael P. Hannigan, Sirine C. Fakra, Brian Majestic Oct 2020

Iron Speciation In Pm2.5 From Urban, Agriculture, And Mixed Environments In Colorado, Usa, Joseph R. Salazar, David J. Pfotenhauer, Frank Leresche, Fernando L. Rosario-Ortiz, Michael P. Hannigan, Sirine C. Fakra, Brian Majestic

Chemistry and Biochemistry: Faculty Scholarship

Atmospheric iron solubility varies depending on whether the particles are collected in rural or urban areas, with urban areas showing increased iron solubility. In this study, we investigate if the iron species present in different environments affects its ultimate solubility. Field data are presented from the Platte River Air Pollution and Photochemistry Experiment (PRAPPE), aimed at understanding the interactions between organic carbon and trace elements in atmospheric particulate matter (PM). 24-hr PM2.5 samples were collected during the summer and winter (2016–2017), at three different sites on the Eastern Colorado plains: an urban, agricultural, and a mixed site. Downtown Denver had …


Behavior Of Iron Species And Free Radicals In Ambient Pm2.5 And Pm Surrogates, Cholena Russo Ren May 2020

Behavior Of Iron Species And Free Radicals In Ambient Pm2.5 And Pm Surrogates, Cholena Russo Ren

LSU Doctoral Dissertations

Air pollution, consisting of ambient particulate matter (PM), has been a rising health concern to the public. PM contains free radicals and have been known to damage human cells; however, their free radical chemistry is not well understood. This study utilized various vacuum and/or heat treatments to study free radical behavior in PM2.5 (particulate matter with an aerodynamic diameter of 2.5 mm or less) and PM surrogates and simulated sunlight effects on PM2.5. To mimic PM, iron-silica catalysts (i.e. PM surrogates) were synthesized and real-world ambient PM2.5 was selected. The free radicals in PM2.5 …


Synthesis And Characterization Of Synthetic Urban Melt Glass, Rebecca Kristien Lowe May 2020

Synthesis And Characterization Of Synthetic Urban Melt Glass, Rebecca Kristien Lowe

UNLV Theses, Dissertations, Professional Papers, and Capstones

Melt glass formed from the explosion of a nuclear device is a unique post-detonation material that can aid in the ensuing forensics investigation. Trapped in the melt glass are chemical and isotopic signatures that can provide diagnostic and source information about the weapon by comparison with documentation of previous detonations. A nuclear terrorist attack would likely take place in an urban environment and as such, the melt glass formed would consist of a complex matrix including urban materials like cement and glass, activation products from the large neutron flux that will be seen, and fission products from the detonation. The …


Reactions Of First-Row Transition Metal Complexes In Bis(Alkoxide) Ligand Environments With Diazoalkanes: Formation Of Carbenes Versus Reductive Coupling To Form Bridging Tetrazenes, Amanda Grass Jan 2020

Reactions Of First-Row Transition Metal Complexes In Bis(Alkoxide) Ligand Environments With Diazoalkanes: Formation Of Carbenes Versus Reductive Coupling To Form Bridging Tetrazenes, Amanda Grass

Wayne State University Dissertations

This dissertation focuses on the design and reactions of novel late transition metal carbene complexes featuring alkoxide ligand environments. The high-valent cobalt carbene Co(OR)2(=CPh2) (OR = OCtBu2Ph), featuring short Co=C bond of 1.773(3) Å, was previously reported from the reaction of Co(OR)2(THF)2 with diphenyldiazoalkane. Magnetic and spectroscopic (EPR) studies demonstrated Co(OR)2(=CPh2) to be a low-spin S = ½ complex. Computational studies, in agreement with experimental data, suggested that the electronic structure of Co(OR)2(=CPh2) lies between intermediate spin Co(III) anti-ferromagnetically coupled to a carbene radical and a Co(IV) alkylidene. This dissertation began with investigation of this complex in carbene transfer reactivity. …


Modeling Iron And Light Controls On The Summer Phaeocystis Antarctica Bloom In The Amundsen Sea Polynya, Hilde Oliver, Pierre St-Laurent, Robert M. Sherrell, Patricia L. Yaeger Jan 2020

Modeling Iron And Light Controls On The Summer Phaeocystis Antarctica Bloom In The Amundsen Sea Polynya, Hilde Oliver, Pierre St-Laurent, Robert M. Sherrell, Patricia L. Yaeger

CCPO Publications

Of all the Antarctic coastal polynyas, the Amundsen Sea Polynya is the most productive per unit area. Observations from the 2010-2011 Amundsen Sea Polynya International Research Expedition (ASPIRE) revealed that both light and iron can limit the growth of phytoplankton (Phaeocystis antarctica), but how these controls manifest over the bloom season is poorly understood, especially with respect to their climate sensitivity. Using a 1-D biogeochemical model, we examine the influence of light and iron limitation on the phytoplankton bloom and vertical carbon flux at 12 stations representing different bloom stages within the polynya. Model parameters are determined by …


Synthesis And Characterization Of Pyridine Dipyrrolide Iron Complexes Relevant To Nitrene And Carbene Group Transfer, Brett M. Hakey Jan 2020

Synthesis And Characterization Of Pyridine Dipyrrolide Iron Complexes Relevant To Nitrene And Carbene Group Transfer, Brett M. Hakey

Graduate Theses, Dissertations, and Problem Reports (ETD)

The synthesis and electronic structures of the square-planar high-spin FeII complexes (MesPDPPh)Fe(OEt2) and (MesPDPPh)Fe(thf) were investigated. Analysis of these compounds using a combination of 1H NMR and 57Fe Mössbauer spectroscopies, in conjunction with computational analysis, has resulted in a rationalization for their unusual electronic structures, which arise from the unique coordination environment enforced by the pyridine dipyrrolide chelate ligand.

The reactivity of (MesPDPPh)Fe(thf) with organic azides has been probed and resulted in the isolation of an array of products that are consistent with …